Growth of novel boron-rich nanocrystals from oxygen-deficient borophosphosilicate glasses for boron neutron capture therapy

Abstract

We develop a new type of boron (B)-rich nanocrystals (NCs) for applications in Boron Neutron Capture Therapy (BNCT). Phase separation of oxygen (O) deficient borophosphosilicate glasses (BPSG) by annealing in inert ambient gas results in the growth of different types of B-rich NCs. When the silicon (Si) concentration is much higher than the others, B and phosphorus (P) co-doped Si-NCs are grown. In the opposite case, cubic boron phosphide (BP) NCs are grown. In between two extremes, we demonstrate the growth of a new type of cubic NCs consisting of B, Si and P with an average B concentration up to 36 at%. The B-rich NCs are dispersible in water and exhibit photoluminescence in the biological window. These properties in combination with the capability of the bio-functionalization via the surface Si–hydrogen (H) and Si–O bonds suggest that the B-rich NCs can be a multifunctional biomaterial used for imaging, diagnosis and BNCT.